Development of HTS power transformers for the 21st century: Waukesha Electric Systems/IGC-SuperPower/RG&E/ORNL SPI collaboration

Abstract

The collaboration among Waukesha Electric Systems (WES), IGC-SuperPower (IGC-SP), Rochester Gas & Electric (RG&E), and Oak Ridge National Laboratory (ORNL) is now in Phase II. This is a US DoE cost-shared Superconductivity Partnership Initiative (SPI) Project, with the objective of developing a conceptual design for a commercial 30-MVA superconducting utility power transformer, and furthermore designing and building a prototype 5/10-MVA transformer that will be operated on the utility power grid at the main WES plant in Waukesha, WI. The design approach for both of these transformers is to place both the core and cold mass inside the vacuum tank. Commercial cryocoolers are used to cool the superconducting windings below 40 K. This approach avoids the use of expensive non-conducting cryostats. It allows a flexible tradeoff between operating temperature and length of conductor to produce a cost-optimized design with the best currently available conductor. Activities in the participant organizations will be summarized as follows: WES—core cooling and conventional component design, IGC-SP—superconducting coil, coil cooling and lead development and cryogenic suspension, ORNL—AC loss measurements, cryogenic dielectric tests, and cryogenic cooling module design, and RG&E—operational needs and utility perspectives.